What's the question boxes displayed in the terminal?

How do I remove the strange question marks with boxes?

The question marks in boxes are characters that your font doesn't include. Usually, getting a font that includes the missing Unicode characters fixes the issue. I would suggest getting a font that has a decent number of Unicode characters in it.

Personally, I like Cascadia Code, but other code fonts that include Unicode should work well (Fira Code is also popular, but there are many other good ones as well).

Download the latest release of Cascadia Code from GitHub. Extract the zip file. There are two main versions of the font in the zip. Cascadia Code and Cascadia Mono. Mono does not include font ligatures (see this image for a with/without). For a terminal, you don't need ligatures, but feel free to use them if you prefer.

Once you've picked either Cascadia Code or Mono (Code has ligatures, Mono doesn't), navigate in the zip file, and into the ttf folder. Find the version you want (pick one with PL at the end)*, and install the font. Once it is installed, go into your terminal's settings, and select Cascadia Code or Cascadia Regular.

I don't know what terminal you are using, but if you are using the standard one that comes with windows (not Windows Terminal, but the default one on Windows 10), this Stack Overflow post explains how to change the font once it is installed.

*This includes PowerLine symbols, which might be nice later if you want those characters